Low Complexity Soft Decision Technique for Gray Mapping Modulation

High order Gray mapping modulation has been widely used in wireless communications, but the traditional soft decision technique via the log-sum approximation is of high computational complexity. In this paper, a low complexity soft decision technique is proposed for popular Gray mapping modulation schemes, including M-PAM, M-PSK and square M-QAM. Compared with the traditional log-sum approximation, the proposed technique can effectively reduce the computational complexity without any performance degradation.

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